This aluminum straight edge is an economical alternative to other much more expensive straight edges on the market. This straight edge is very helpful to determine machine table flatness and in setting up machines such as jointers and planers and various out feed tables. Reference edge is machined flat to within 0.001″ over the entire length. They are available in three different lengths. Guaranteed straight to within 0.001” (that’s thousandth of an inch!) over the entire 24” length Anodized aluminum .0400” (7/16”) thick by 1.750” (1 ¾”) wide Reference edge is machined flat and smooth Contoured cross section for easy gripping Hanging hole on end